Aircon Chilled water Expansion Tank
Aircon Chilled water Expansion Tank
(OP)
I have a Chiller system installed at the basement floor with the chilled water expansion tank installed at the roof top at 37.4m height relatively to the chiller unit. The highest chilled water pipe is at 32m. The expansion tank is gravity fed to the chilled water pipe system. There is a bypass valve from a pressurized water supply of 25psi at the expansion tank for maintenance purpose of fast filling the chilled water.
I have noticed that during the normal chiller operation with the bypass valve on, the chilled water will be further pressured from 59psi to 74psi with an increase of 5psi (reading taken from the chiller unit at the basement) from the pressurized bypass. However, the chiller operation efficiency seem to be increased by 10%.
My question is can I left the bypass on all the time to have the increase chiller performance?
I have noticed that during the normal chiller operation with the bypass valve on, the chilled water will be further pressured from 59psi to 74psi with an increase of 5psi (reading taken from the chiller unit at the basement) from the pressurized bypass. However, the chiller operation efficiency seem to be increased by 10%.
My question is can I left the bypass on all the time to have the increase chiller performance?





RE: Aircon Chilled water Expansion Tank
Please explain how this increase in efficiency was determined or calculated, and please define what you mean by "operation efficiency". Usually chiller efficiency is determined by Tons refrig/KW input.
RE: Aircon Chilled water Expansion Tank
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RE: Aircon Chilled water Expansion Tank
I would start by checking the data.
That type of expansion tank is supposed to be vented to the atmosphere.
RE: Aircon Chilled water Expansion Tank
The centrifugal chiller panel will show an average of additional 10% unloading.
RE: Aircon Chilled water Expansion Tank
RE: Aircon Chilled water Expansion Tank
Anyway, I think the improve in performance could be due to the increased in water pressure have totally eliminated the air binding or cavitation in the system. However, I am interested to know if there is no expansion tank connected (literally) but with the bypass valve open, what untoward impact will it happen to the aircon system that I should take note?
RE: Aircon Chilled water Expansion Tank
If not, and if your system is like 90+ percent of the systems today (a bladder tank with basically an air bag with a factory pre-charge of 12 psig) you have a leaking bladder. Please don't take this personally. Just call Taco (or whomever sold you the tank) and replace it.
RE: Aircon Chilled water Expansion Tank